The present invention relates to spectacles, and more specifically to spectacles comprising an eyeglass frame in which at least one transparent element acting as a glass can be inserted, and at least one holding means in which a magnifying lens can be disposed in each case.
Spectacles of this kind, preferably provided with two magnifying lenses, are worn in particular by persons carrying out tasks in a field of activity requiring magnification. Such activities are performed in particular in fields of medicine, fine mechanics and electronics. These magnifying lenses are designed as objectives which are fixed to a pair of spectacles by means of a holding device.
One known design shows spectacles of this kind on whose eyeglass frame a bearing mechanism is mounted having a bearing arm, running transversely, on the ends of which the magnifying lenses are fixed so that they come to be situated in front of the pupil of the respective eye of the wearer.
These devices are complicated and impede a clear view, owing to the necessary bearing elements located in the field of vision of the wearer. To adjust the magnifying lenses, mechanisms are needed that are costly to manufacture and time-consuming to operate.
Spectacles are also known in which the magnifying lens systems, disposed in objectives, are stuck on the eyeglass lenses. Compared to the devices mentioned above, the result is that the vision of the wearer of these spectacles is no longer restricted by additional bearing elements. Disadvantageous, however, is that the affixing of the objectives containing the magnifying lens systems must take place individually for each wearer of spectacles of this kind since the interpupillary spacing varies from person to person. Therefore manufacture must be carried out individually for each wearer, which is very costly.
With these prior art spectacles with magnifying lenses, both spectacles having non-prescription lenses and those with prescription lenses can be used. In the case of both aforementioned prior art types of spectacles with magnifying lenses, these magnifying lenses can be aligned in such a way that the magnifying lens axes intersect at a distance from the eyes corresponding to the distance of the field of activity from the eyes.
The object of the invention consists in designing spectacles with magnifying lenses in such a way that the mutual spacing of the magnifying lenses can be easily adapted in each case to the interpupillary spacing of the respective wearer, and the magnifying lenses can be exchanged in a simple way.
This object is achieved according to the invention in that the at least one holding element comprises a slot-shaped aperture made in the transparent element, which aperture has a longitudinal axis that is aligned substantially parallel to the imaginary line of spacing between the pupils of the eyeglass wearer, and in which slot-shaped aperture the magnifying lens is inserted and is displaceable in the longitudinal axial direction of this slot-shaped aperture, and wherein a clamping device is provided with which the magnifying lens can be held, clamped, in adjusted position in the slot-shaped aperture of the transparent element.
With this solution according to the invention the magnifying lens spacing can be adjusted to the interpupillary spacing of the wearer of these spectacles. The length of the slot-shaped aperture can be selected in such a way that practically the entire range is covered within which interpupillary spacing values vary. It is also conceivable that the disposition and the length of the slot-shaped apertures are designed in such a way that a first type is foreseen for wearers having a small interpupillary spacing, a second type for wearers with an intermediate interpupillary spacing, and a third type for wearers with a large interpupillary spacing.
The clamping device is preferably formed by a flange and a threaded part, whereby, in the state of being placed on the transparent element, the flange is supported on the one side of the transparent element, and the threaded part projects through the slot-shaped aperture. A nut can then be screwed onto the threaded part, which nut is supported on the other side of the transparent element, whereby the flange can be pressed against the transparent element, and thus a clamp mounting achieved. This embodiment is easy to manufacture and operate.
The flange and the threaded part are preferably designed as a first sleeve-shaped element provided with a continuous bore in which the magnifying lens is insertable. In this way the magnifying lens can be easily exchanged, in particular if the magnifying lens is inserted in the bore and held by friction.
Another preferred embodiment of the invention consists in that insertable coaxially in said first sleeve-shaped element is a further sleeve-shaped element which is rotatable about a rotational axis, and provided in the further sleeve-shaped element is a further continuous bore, in which the magnifying lens is inserted, the axis of the bore being inclined by an angle a with respect to the rotational axis. The magnifying lens can have the shape of a cylinder whose axis coincides with the magnifying lens axis, making possible the use of simple magnifying glasses. Adjustment of the magnifying lens axis can take place by rotating the further sleeve-shaped element with respect to the first sleeve-shaped element.
A rotational mechanism can be provided to simplify this rotation of the further sleeve-shaped element with respect to the first sleeve-shaped element, and to make it more precise. At the same time a stop device can be provided, making possible a stopping of the rotation.
The magnifying lens is preferably displaceable in the direction of its longitudinal axis with respect to the transparent element. The distance of the magnifying lens from the eye can thereby be optimally adjusted.
The slot-shaped apertures for receiving the magnifying lenses can be made in two eyeglass lenses mounted on the eyeglass frame. However, they can also be provided on a protective shield that can be placed on the eyeglass frame. The protective shield, provided with magnifying lenses, can be placed on an eyeglass frame having no additional eyeglass lenses, or it can be placed on an eyeglass frame in which eyeglass lenses have already been inserted. The protective shield, with the magnifying lenses inserted therein, then comes to be situated in front of these eyeglass lenses. When the magnifying lenses are not being used, the protective shield with the magnifying lenses can thus be removed from this eyeglass frame provided with eyeglass lenses. The wearer is then wearing a normal pair of eyeglasses, it being possible for the eyeglass lenses to be prescription lenses.
Embodiments of the present invention will be explained more closely in the following, by way of example, with reference to the attached drawing.